Professional stereo microscopes are recommended for research institutes and corporate users for daily routine work. Usually designed with advances CMO (teescopic) optics with paralell beampath which provide high line-resolution in the object plane. Continous zoom is a basic feature. Their optical system is corrected on a high level, including apochromatic models with almost no visible chromatic aberrations. The outstanding optics comes with large microscope stage and robust mechanical design, optionally with phototube and various accessories and illuminations.